FLOWERING PLANTS AND FERXS OF ARIZONA 101 



2. Glumes'acute or abruptly awn-pointed, symmetric, the nerves evident (3). 

 3. Lemmas glabrous or obscurely pubescent; rhizomes more vigorous and 

 spikelets usually more implicate than in A. dasystachyum. 



2. A. RIPARIUM. 



3. Lemmas usually densely pubescent 3. A. dasystachyum. 



1. Plants cespitose, without rhizomes (4). 



4. Lemmas awnless; internodes of the rachilla villous; glumes broad, nearly as 

 long as the spikelet 4. A. trachycaulu.m. 



4. Lemmas distinctly awned (5). 



5. Awns erect or nearly so 5. A. subsecundum. 



5. Awns divergent, at least when dry (6). 



6. Rachis finally disarticulating; glumes long-awned, the awns often as 

 long as those of the lemmas (7). 

 7. Culms prostrate or decumbent-spreading, often flexuous; panicles 

 nodding or flexuous 6. A. scribxeki. 



7. Culms erect 7. A. saxicola. 



6. Rachis continuous; glumes acute or with a very short awn (8). 



8. Spike straight, 8 to 15 cm. long; spikelets appressed, the awns ab- 



ruptly divergent; blades 1 to 2 mm. wide 8. A. spicatum. 



8. Spike flexuous, 15 to 30 cm. long; spikelets somewhat spreading, the 

 awns divergent but not abruptly so; blades 4 to 6 mm. wide. 



9. A. ARIZONICUM. 



1. Agropyron smithii Rydb., N. Y. Bot. Gard. Mem. 1: 64. 1900. 

 Apache, Navajo, Coconino, Yavapai, and Pima Counties, 3,000 to 



7,000 feet, dry hills, moist open ground, and pine forests, May to 

 September. New York to Alberta and Washington, south to Ken- 

 tucky, Texas, Arizona, and California. 



A form with pubescent lemmas is var. molle (Scribn. and Smith) 

 M. E. Jones, and one with densely pubescent sheaths is var. palmeri 

 (Scribn. and Smith) Heller. 



2. Agropyron riparium Scribn. and Smith, U. So Dept. Agr., Div. 



Agrost. Bui. 4: 35. 1897. 

 Kaibab Plateau, Coconino County (Storm 225) . Dry or moist 

 meadows and hills. North Dakota to Alberta and Washington, 

 south to Colorado, northern Arizona, and Nevada 



3. Agropyron dasystachyum (Hook.) Scribn,, Torrcy Bot Club Bui. 



10: 78. 1883. 



Triticum repens var. dasystachyum Hook., Fh Bcr. Amer. 2: 254. 

 1840. 



Arizona, without locality. Plains and sandy shores, Michigan to 

 British Columbia, south to Illinois, Nebraska, Colorado, Arizona, and 

 Nevada. 



4. Agropyron trachycaulum (Link) Malte, Natl. Mus. Canada Ann. 



Rpt. 1930: 42. 1932. 



Triticum trachycaulum Link, Hort. Berol. 2: 189. 1833. 

 Agropyron tenerum Vasey, Bot. Gaz. 10: 258. 1885. 

 Agropyron pauciflorum (Schwein.) Hitchc, Amer. Jour. Bot. 

 21: 132. 1934. 



Apache County to Mohave County, south to Cochise and Pima 

 Counties, 5,000 to 9,000 feet, moist meadows and open woods. May 

 to October. Labrador to Alaska, south to West Virginia, Kansas. 

 Arizona, and California. 



